Joshua’s RV-9A Project

Two steps forward, .8 steps back…  Allison came out tonight and helped with riveting — we did both fore & aft rows at the center section bulkhead, and the outboard floor stiffeners.  About 5 minutes after we finished the floor stiffeners, I came to the realization (through a convoluted thought process) that the left and right outboard floor stiffeners had been transposed when clecoed in.  (I must have mismarked them after etching and priming.)  Essentially, this meant that the vertical leg of the angle was toward the outside of the fuselage, instead of the centerline.  Looking ahead in the plans, I could see no problems this would cause, except for two things: first, the panels which hide the fuel & brake line runs would need to be altered, to move the notch for the vertical leg of the stiffener angles outboard about 1″; and second, any carpet underlayment foam would have to be cut to non-standard dimensions…not a big deal, but something to remember when ordering interior stuff, since the foam often comes with the carpets.

After some internal debate, I decided that I would just drill the things out, swap them, and be done with it.  50 rivets to drill out, all of which went fine without any problems.  We’ll re-set these in tomorrow’s batch.

With Allison helping tonight, wrapped up the remaining right skin rivets, and did all the left skin rivets.  Bottom side left to go.

Riveted most of the right side skin with Allison.

Progress is being made on the fuselage riveting…I first set the two remaining rivets on the inboard floor stiffeners, then clecoed in the armrests and baggage side wall ribs.  The lower longerons were bolted to the firewall weldments; torqued, sealed, and the bottom floor skin clecoed in place, followed by the outboard floor stiffeners.

With all the components now clecoed together, there’s nothing left to do but rivet!  Working from a stepstool as a seat, I was able to reach about 2/3rds of the way up the side walls, and completed everything I could reach back to the 705 bulkhead, along with all the longerons and bulkheads aft of the 706.  I should be able to get most of the baggage walls and 705/706 bulkhead-skin rivets in a similar manner.  I was also able to reach about half the rivets joining the side skin to the outboard seat ribs, by reaching through the aileron pushrod holes.

Finished up a couple odds ‘n’ ends, and started the fuselage riveting tonight.  I had read that the rivet immediately above the rear spar bars can interfere with the rear spar stub on the wing, so I dimpled that location for a flush rivet.  Also pre-riveted the center section doublers to the side skins as called for (though the plans call out 5 and 6 rivets, I believe they mean 6 and 7; Smitty came to the same conclusion.)  Riveted the angled side ribs to the skin on all rivets that aren’t shared with the side skin; this required temporarily removing the bolt from the rear spar to gain access to the rivet tail.

With those preparatory steps out of the way, it was time to marry the tailcone and center fuselage for the final time.  Once the double row of holes on the bottom was clecoed, I added the longerons and clecoed up to the 904 bulkhead, then added the side skins and clecoed those in place.  Firewall is added next–the angles clips and side stiffeners must be riveted to the firewall at this point if not already done, as access is limited once the side skins go on.

After the firewall was in place, I added all the structural pieces between the 904 and the firewall.  Squeezed the accessible rivets on the inboard floor stiffeners in preparation for adding the forward bottom skin.  Shortly after that, I squeezed my left pinkie finger, so it was time to call it a night.  The aftmost rivets on the floor stiffeners will need to be set with the gun, as they’re tucked too far under a flange to get at with the squeezer.

Sprayed interior color on most of the batch of parts — the side skins and longerons remain.  I will pick up a quart can of the paint to do the side skins, as they would be rather tedious to do with a rattle can…

Etched the skins and longerons, then shot primer on all the parts.  Interior paint later this week, and with any luck, final assembly can begin on the weekend.

Etched all the fuselage components that are done to date, except for the side and forward bottom skins, and the main longerons.  Those are big enough that they really need to be done outside (the etch solution eats the concrete floor, and they’re too big to fit in the big plastic tray I use for etching parts); we’ll see if the weather is good enough tomorrow to get it done.  Should be able to get the priming done this week.

After tiring of etching, I thought I’d look at the install of the crotch strap brackets.  This is where I discovered a dormant screw-up that I was previously unaware of.  Turns out that when I initially fit the seat ribs to the center section, I got the inboard pair of F-916 ribs reversed.  That is, the inboard F-916-L goes on the right side, and vice versa.  Unlike some other parts of the plane, it’s completely possible to reverse these with no ill effects–the seat pans, bottom skin, and everything else all fit perfectly, so nothing screamed “wrong!”  Until I held the crotch strap brackets in place, when it became very evident what had happened.  The space between the ribs that are spanned by the bracket is about 3/4 of an inch too wide.  Since the center section isn’t yet attached to the tailcone, access to drill out and re-rivet these ribs isn’t a problem, so I drilled both out and put them in the correct orientation.  Easy enough, except for one thing: the 3/16″ holes that were match-drilled from the main spar, where AN3 bolts are inserted, are not in alignment with the line of rivets that runs down the forward flange of the ribs, but rather offset by a small amount.  This means that when the already-drilled ribs were flipped into the correct orientation, those 3/16″ holes are out of alignment by about 1/2-diameter, which would result in ovalled holes if drilled.  I’ve sent an email off to Van’s asking their advice–my guess is that they’ll say it’s fine, put in the bolt and move on, since that rib is also held in by a bunch of rivets.  But better to ask…if the ribs need replacing, it should be easy to do that, too…for $17.73 apiece, plus shipping.  Sigh.  I feel like I’ve made several stupid mistakes lately.

(The ribs in question are the third in from each side on the drawing — the inboard “F-916-L/R outboard seat rib”.  Marked by the clecos on the second photo.)

Finished the final deburring on the side skins, and dimpled the three skins with help from Allison.  Fuselage parts are now ready for priming, which will probably be next Sunday when I next have a large block of time to spend.

Countersunk the main longerons, and deburred all the drilled holes in the side skins.

Crossed the 700 hour mark tonight, as well.